Method of plugging holes in metal plates



M. LACHMANA MEIHUD OF museum HOLES m METAL PLATES.

APPLICAHON FILED GET. I9, 9&8,

Patented Mar. 2, 1920.

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WISH

UNITED STATES PATENT OFFICE.

MAURICE LACHMAN. OF NEW YORK.

N. Y.. ASSIGNOR TO UNIVERSAL ELECTRIC WELDING COMPANY. OF NEW YORK. N. Y.. A CORPORATION OF NEW YORK.

METHOD OF PLUGGING HOLES IN METAL PLATES.

Application filed October 19.

Be it known that I. Maunn'i: liu'iniax, a. citizen of the United States. and a resident of New York. in the county of Ken York and htatc of New York. have invented certain new and useful Improvements in Methods of Plugging Iloles in Metal Plates. ot' which the following is a specification.

My present imention relates to a method of plugging holes in metal plates particularly of such heavy gage as ship plates wherein it is nceessanv to have the plugged hole of practical uuit'orm quality and strength with the imperforatc part of the plate.

In ship huilding the rivet holes in the plates are provided in the mill before shipment to the yard and it frequently happens that the holes when the plates are about to be assembled are. found to he in the wrong place through numerous different causes. This requires that the holes he filled up and obviously the refilled hole should he as strong as other parts of the plate. The

methods at present employed for accomplishing this refilling operation require considerable time and do not result in a uni formly strong plate.

The object of the present invention is to plug up the hole in a quick, ellicicnt manner and attain a plate of uniform strength.

In carrying out the invention I employ a heating electric current derived from the secondary of a transformer as is done in the electric metal working and welding art to heat an insert located in the hole to. be plugged and for this purpose any of the Well known electric heating and welding apparatus of the resistance type may he cmployed.

The invention consists in the improved method of plugging holes in metal plates hereinafter more particularly described and then specified in the claims.

In the accompanying drawings, Figure 1 is a diagranmiati representation of an arrangement for carrying out the present invention.

Fig. 2 is a similar view showing a subsequent stage in the operation. v

Fig. 3 is a similar view showing the cm pletion of the final step in the process. I

1 indicates a metal plate such as a, plate having a hole it is desired to Specification of Letters Patent.

'atentcd Mar. 2. 1920.

1918. Serial N0. 258.854.

2 indicates a metal insert or plug ol' the same contour as the hole in the plate and adapted to tit the hole snugly when cold.

The insert or plug is passed through the hole and is left with its opposite ends -projccting a short di tance from opposite surfaces ol' the plate.

The work is placcd hciwccn currcnt supplying hlocks or electrodes ll. -l forming the opposite terminals of thc sccondar circuit of a transformer .3. The llltitltw are hrought into contact a ith the projecting ends of the insert '3 and a current passcd from one to the other through the insert in a manner we undcrslood h those skilled in. the electric welding art.

The passageol' the current from one block t the other heat the insert midway hetween its ends and h v continuing the current the middle part of the inscrt attains a welding heat and also causes the walls of the hole to rise to such heat hy conduction. By applying pressure in any suitahlc. well known manner the hlocks 3 and 4 are caused to approach each othcraud in sodoiug bulge out or upset the heated section of the insert laterally against the walls of the hole and cause a welding of the parts as indicated at it) in Fig. 2

The continuation of the current causes the. projecting ends oi the insert to heroine heated and in applying the pressure these ends upset as indicated in Fig. .2 and mushroom over onto the outer surfaces of the plate 1. lVhen this takes place. a larger path for the current is provided which then passes through the plate 1 as well asthrough the insert. This passage of the current causes the whole mass of the insert as Well as the parts of the plate around the hole embraced by the mushroomed ends of the insert to hecome. plastic and the pressure hetwccn the blocks eoalesces the parts and w lds them together into an integral mass. the hlocks hcingpressed toward each other until they seat in the opposite surfaces of the plate. BYJlllS time the ends of the insert have hecpft'ne. flush with the outer surt'aces of the late as indicated in Fig. 3.

In plugging a hole according to this invention it is impossihlc to observe the insert in the finished product even when the plate is cut or sawed directly through the plugged hole as the whole insert has become an inte ral part of the plate. In Fig. 3 the dotm5 lines 11 merely indicate how the insert has become embedded in the plate.

What I claim as my iurentmn is:-

1. The method of plugging holes in metal plates, consisting in inserting a metal plug through a hole in a metal plate with its ends projecting from opposite sides. passing an electric current through the plug and applying pressure to weld the plug tn the plate and at the same time mushroon'l the projecting ends onto the opposed surfaces of said plate and then flatten the mushroom parts flush with the opposite surfaces of the plate.

2. The method of plugging holes in metal plates, consisting in passing a metal insert through a hole in a metal plate with its ends projecting from upposite surfaces 0f the plate, contacting; current supplying electrodes to said. pro ecting ends, passing an electric current from one electrode to the other to heat the insert in the hole and applying' pressure to weld the insert to the walls of the hole and at the same time mushroom the projecting ends ever opposite surfaces of the plate and weld them to the plate flush with the outer surfaces thereof.

Signed at New York, in the county of New York and State of New York, this 18th day of October. A. I). 1918.

MAURICE LACHMAN.

Witnesses:

' C. F. TISCHNER,

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